XENACANTHUSdecheniThis fresh water shark was characterized by
a large spine protruding from the back of its head as well as
little forked teeth. Since it did not possess true bone, mostly
spines and teeth are discovered giving a rather limited view of
this interesting animal.

TIME
- 345 MYA, Carboniferous period. Some species survived into the
mid - Permian period.RANGE
- USA - Texas, Oklahoma, Kansas, New Mexico. Fossils of this shark
are also found in Russia and some sites in Eastern Europe.